Nanoscale inhomogeneity of Earth's constituent materials studied by in-situ small angle X-ray scattering under high pressure

我们已经开发了高压下原位小角X射线散射测量技术。现在可以在金刚石压砧单元中收集小样品的数据，Q范围约为0.1至2.0 nm-1。迄今为止，用这种新技术测量了三种类型的非晶态SiO_2，并得到了下列有趣的结果：（1）在石英玻璃和气相二氧化硅的实验中，即使在高达50 GPa的最高压力下，晶粒和晶粒边界之间的密度差也没有完全减小，以及（2）在高达20 GPa的实验中，中孔二氧化硅的孔径随着压力的增加而增大。

We have developed techniques for in-situ small-angle X-ray scattering measurement under high pressure. It is now possible to collect data for small samples in a diamond-anvil cell at a Q-range approximately from 0.1 to 2.0 nm-1. Three types of noncrystalline SiO2 have been measured so far with the new techniques and the following interesting results have been obtained; (1) the density difference between grains and grain boundaries did not completely diminish even at the highest pressure in experiments for silica glass and fumed silica up to 50 GPa and (2) the size of pores enlarged with increasing pressure in experiments for mesoporous silica up to 20 GPa.